1. Field of the Invention
This invention relates generally to a volumetric fluidics pump, and more specifically to pump including a shaft or rotor that moves relative to a fluidic channel.
2. Description of the Related Art
Volumetric pumps may be advantageously utilized in a broad range of applications and offer various advantages such as precise control of a volumetric flow rate and preservation of a sterile environment. For example, in ocular surgical applications such as cataract surgery, peristaltic pumps are often used to maintain a critical balance between the flow of fluid into and out of the eye.
In a typical system, the peristaltic pump comprises a tube or channel that is continually closed between a ramp and one or more rollers disposed about a rotating pump head. As the pump head rotates, a first rollers engages the tube on an inlet side and draws fluid into a tube section that is subsequently sealed off by an adjacent, second roller. Once the tube section is sealed, the first roller opens the tube, thus allowing the second roller to push entrapped fluid out of the tubing section, while simultaneously drawing in new fluid. In order for the roller to close off the tubing, the mating ramp is arcuate in shape and generally has a radius of curvature that equals the sum of the radius of the circular roller path plus the thickness of the tube as it is squeezed between the ramp and one of the rollers.
One problem with such peristaltic pump designs is that in order to prepare the pump for operation, the ramp must be displaced from the pump head, the pump tubing arranged around the rollers, and the ramp moved back into place over tube. In addition, a relatively complex and expensive latching mechanism may be required to keep the tubing engaged between the rollers and ramp. Another potential problem is the time and difficulty involved in arranging the tubing around the rollers, which usually requires two hands.
In light of these problems, improved volumetric pumping devices and methods are needed that provide less expensive pumping components and simpler installation procedures.